Search

The aim of this research was to examine the correlation among college students' physical activity, social–emotional abilities, gender and their perception of social support. The survey was conducted among 408 college students from Jiangsu, Shandong and Hubei provinces utilising the Perceived Social Support Scale, the Social–Emotional Competence Scale for Chinese College Students and the Physical Activity Scale (PARS‐3). SPSS 27.0 and the Process 4.1 plug‐in developed by Hayes were used to perform common method bias tests, independent samples t‐tests, descriptive statistics, correlation analyses, and moderated mediation model tests on the data. (1) After controlling for variables such as educational attainment and professional background, physical activity was found to exert a significant and favourable influence on college students' perception of social support (β =.11, p<.001). (2) The relationship between physical activity and college students' perception of social support was moderated by their social–emotional skills. The mediation effect size was calculated to be 54.33%. (3) Gender moderates the relationship between physical activity and college students' perceptions of social support (β =.09, t = 2.01, p<.05). Physical activity not only directly affects college students' perceived social support, but also indirectly through social–emotional competence; gender has a significant moderating effect on the direct effect of physical activity on college students' perceived social support. Specifically, female students had a more significant positive predictive effect on perceptual social support than male students. Please refer to the Supplementary Material section to find this article's Community and Social Impact Statement. [ABSTRACT FROM AUTHOR]

Although remarkable development of titanate‐based glasses has been achieved, challenge remains to elucidate the correlation between structure and glass‐forming properties in these systems due to their complex structure that is inconsistent with the classic Zachariasen's model. In this work, we aim to correlate the structural evolution of titanate melts to their glass‐forming ability (GFA). The prototypical material barium dititanate (BaTi2O5, BT2) melts with different GFA were rendered by controlled melting atmospheres, and the corresponding structural changes were determined using in situ high‐energy synchrotron X‐ray diffraction combined with empirical potential structure refinement and ab initio molecular dynamics. The results show that BT2 melt in reducing atmosphere shows poor GFA but that in oxidizing atmosphere presents good GFA. Structural analysis demonstrates the mean coordination number of [TiOm] polyhedra is analogous in the melt under two different atmospheres but an enhanced heterogeneous cations aggregation takes place in the melt under reducing atmosphere, which is closely related to oxygen‐deficiencies. Furthermore, we reveal that the enhanced heterogeneous cations aggregation promotes crystallization (and therefore hinders glass formation) through disordering the distribution of [TiOm] and [BaOn] polyhedra, changing the connectivity between these polyhedra, creating more crystal‐like Ti‐Ti clusters, and decreasing topological disorder of BT2 melt. Our work provides a new viewpoint to understand the GFA of titanates melt from structural heterogeneity beyond the previous perspectives that only focus on [TiOm] polyhedra. [ABSTRACT FROM AUTHOR]

The study presents a profile design method to improve the wear performance of misaligned water‐lubricated bearing based on the modified Archard model. This method takes into account the variation of the film thickness under the mixed elastohydrodynamic lubrication (mixed‐EHL). A transient hydrodynamic Reynolds equation model with the Patir–Cheng flow factors is used to predict the evolution of the mixed‐EHL performance over time. The Archard model is extended to predict the time‐varying wear based on the fatigue concept. To verify the effectiveness of the proposed profile design method; the simulation results, including the transient contact pressure, wear depth and wear volume, between the considering and not considering the profile design are compared. To gain insight, several illustrative examples are presented to show the amelioration of the profile design. Parametric studies are reported to show the applicability of the profile design and emphasise the profile height selection. Therefore, the profile design is an extraordinary method to reduce the edge wear. [ABSTRACT FROM AUTHOR]

Nitrile butadiene rubber is widely used in water‐lubricated bearings due to its excellent performance. Generally, the friction coefficient of water‐lubricated rubber bearings typically between 0.05 and 0.18. In this study, a new method for preparing nitrile butadiene rubber with micro‐holes surface is developed by porous leaching with salt as pore forming agent. The possibility of using porous surface to minimize friction and wear of rubber materials is researched. The influence of structural parameters, including the hole density and size (which are determined by salt mass fraction of rubber compounds and salt grain‐sized, respectively) on tribology performances are also evaluated. In a ring‐on‐block test, the optimal parameters of modified rubber achieved a low friction coefficient of 0.008, which reduced by 42% compared with untreated one (0.019) under the same operating condition. It can be expected that the developed method is beneficial to reduce the friction coefficient of rubber‐steel friction pair under water lubricated condition. [ABSTRACT FROM AUTHOR]

SUMMARY In an opportunistic spectrum sharing system, secondary users (SUs) opportunistically access the white space spectrum that is not occupied by the primary user (PU). Some analytical performance models have been available based on Markov chain modeling. In these models, SUs and PUs access the spectrum by randomly selecting the available channels with equal probability. However, how SUs and PUs use the spectrum are controlled by the access strategy designed in their MAC layer in an ad-hoc network or centralized radio resource management layer in an infrastructure-based network. To analyze the grade of service (GoS) of the secondary system under consideration for the access strategy, we propose an access rule transition matrix to model the access behavior of radio resource management, and apply it into the continuous-time Markov chain model. It was proved that the proposed model is equivalent to the original models assuming the random access strategy by simulation. Moreover, we analyzed the GoS performance of the secondary system by assuming an ordered hunt access strategy. The results showed that the GoS performance of secondary systems can be improved greatly if it knows the spectrum access strategy of the primary system. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]